There are several options, but basically whatever system you use, be consistent.

Sort your mail by creating a place for those pieces of mail that are most likely bills and letters. Hold these until you can share them with a family member or someone you trust who can read them to you. Catalogs and magazines are obviously easy to distinguish from envelopes. Also advertisement offers often come in odd-size envelopes, but if in doubt put them in the pile to be sorted by your 'reader.'

Organizing systems can utilize something you already own or you may buy something from your local office supply store. You can use file folders of different colors or sizes, giant/medium sized manila envelopes, in/out stacking trays, or you may have a specific drawer in the kitchen that holds the mail or a basket on the counter. You will need to decide what works best for you. But whatever you use — try to be consistent.