How to find a job?Watch
Indeed is probably the best place to find jobs at larger chains but some smaller businesses may take you on if you ring them up and ask.
If you don't know where, good options for young people are in shops, cafes or restaurants. Keep in mind a lot of supermarkets require you to be over 18 so if you're younger maybe go for even a post office or corner shop. It might be useful if you have a family member or friend working somewhere like this to put in a good word for you.
Because of covid, I know there aren't many jobs around at the moment and they are very competitive so you may have to just go with what you can get.