Buying a new rear wheel My rear wheel is very bent and I need a new replacement, but I'm not sure on which wheel I'm supposed to get for my bike I was told I could get a freewheel but I don't know what that means. I assumed it was like getting a new front wheel
This is the information I believe may be relevant that I know about my bike, it has:

Shimano Cassette CS-HG41 7 Speed 11-28T
Shimano BB-UN26 68 X 122.5mm - Shimano BBUN26
68 X 122.5mm
SHIMANO CHAINSET 48/38/28 170 M171


I believe the rim size is 700 x 38c - 28 but I'm not too sure so I have attached an image of the tyre below
"700 x 38c - 28 "  You have a "700c" sized road tyre, in width of 38mm and the rim is 28 mm wide.  This tyre size is also known as 622-38 because it is 622 mm across.

A freewheel and freehub are the two different parts that do the same job.  Your bike might have either, but not both.  This is how the cogs in the middle of the rear wheel attach to the wheel's hub.

If you replace the rear wheel completely, you can reuse the tube and tyre.  You will need new rim (28mm wide) and rimtape.  New spokes, and a new hub.  If the cassette and chain are unworn you can transfer them over.
Your cassette is a "shimano branded CS-HG41 with 7 speeds" so its not the old-style freewheel


  For other readers, if the current hub were a freewheel (screws off) then replace it with a cassette that slides onto the hub and is held on with a lockring.  This will mean a new chain.  Freehubs are technically superior to Freewheels.


Your bike has 7 speeds in the rear, so either stick with that or if you want more gears then you'll also have to change the right-side shifter as well.  Don't feel compelled to upgrade the number of gears.