Any camera that’s beyond the basic point-and-shoot will have a mode setting - it’s often a dial on the top plate, on the right, but it varies, especially on lower-end cameras. Among other things, they’ll usually have some plain letters on them, including A, S, M and P. Confusingly, ‘A' might be ‘Av’, and ’S' might be ‘Tv’ (Time value). Because you have a Canon, and Canon wanted to be different. On most modern cameras, there are other modes on there too, usually including some sort of ‘auto’, or ‘intelligent auto’, and often including some sort of 'scene’ modes, and custom settings you can save.
If you just want to get a shot of what’s in front of you, and you don’t want to worry about settings, the most automatic mode is usually a good bet. Panasonic cameras generally have a very good ‘intelligent auto’ mode that works well in most circumstances. My old Sony NEX had both ‘intelligent auto’ and ‘superior auto’ - both are pretty good, with the ‘superior’ version being allowed to do a few more tricks (like taking several shots very quickly and putting them together). Failing that, almost all will have P, for Program, mode, which is near enough the same thing.
When you're starting out, don't let anyone shame you for using automatic modes. They're fine. Learning composition is far more important. If the first thing you're learning with a camera is how to change all the settings, you probably won't take good photos. Learning to take decent photos first, then learning to control the camera better to polish them is a perfectly good plan.
If you want to take a bit more control of the camera, though, you’ll need other modes. So, what are the ‘standard’ set of modes?
- P: Program. Quite similar to the even more auto modes, the camera picks its own shutter speed and aperture to get the shot, balancing the two as it thinks it should. Usually, it will set ISO too, but you can probably turn that on and off in this mode. On some cameras, the flash will pop up automatically in the fully automatic modes, but won’t in Program mode. Good if you don’t care too much about the settings, but don’t want the camera, for example, firing flash on its own.
- A: Aperture Priority. You choose the aperture, let the camera pick a shutter speed to get the ‘right’ exposure. This is the mode I use almost all the time, because the aperture is important to me. When I was first learning photography, I had a Canon AV-1, which only really had aperture priority. Back then, it was because I wanted the fastest possible shutter speed. Now, I use it mainly to control the Depth of Field. It's also ideal for using legacy lenses, because the aperture is set manually on the lens.
- S: Shutter Priority. You choose the shutter speed, the camera picks the aperture, to get the ‘right’ exposure. This isn’t a useful mode for my photography, but might be for something you do. Some action (sports, wildlife, etc) photographers use it, and it can be a quick way to enforce a slow shutter speed to blur something like moving water. Street photographers often use it so they know they have a fast enough shutter speed to freeze people walking.
- M: Manual. You’re on your own. Too much like hard work for me. I only ever use manual mode when I want to take long-exposure shots, which the camera can’t really meter for anyway. Might as well use manual if it’s going to be trial and error anyway. Other than that, I let the camera work it out, and only step in if it’s getting it wrong, which doesn’t often happen. Some people say you’re not a real photographer unless you’re shooting manual all the time. Fuck them.
Other stuff you might have in there, but depends on your camera:
- Scene modes - things like ‘landscape’, ‘sport’, ‘portrait’. I never really used these when I had them, but there’s no reason not to if they match the sort of shot you’re going for. Landscape will probably set a narrow aperture to get plenty of the scene in focus. Sport will try to get a fast shutter speed, probably upping the ISO to keep up with the action if it needs to. Portrait will usually go for a wide aperture to blur the background, and might also set things like skin smoothing, and prioritise focussing on a face. You’d need to see your camera’s manual to find out what they do, or just try them out.
- Custom modes, sometimes marked ‘C1’, ‘C2’, etc. These didnt exist on my NEX-6, and I really wanted them. Later, my A7 had them, and I did't really use them. You can set a whole lot of different settings as you want them for a certain type of shot, and store them all in the custom mode. When I had the NEX, I thought I’d keep one set for B&W, with autofocus, face priority and continuous shooting, to use for street photography; and aperture priority, colour, with single spot focussing and no face detection, for when I’m picking out details in strange things. They can be quite handy if you do more than one ‘type’ of photography, as most of us do. In practice, though, I was only using manual 'legacy' lenses by then, so there weren't many settings I tweaked often enough to use them.
- Other ‘special’ modes. My NEX, for example, had another setting on the dial for auto-stitched panoramas, which I’d really rather was hidden away with the scene modes.