Hello @Rita2164 and welcome to ABB CC from across the lands and seas in New Zealand
The most important thing with sheets is that they fit the bed snuggly.
Make sure you have sheets with plenty of overlap if they are flat sheets.
Hospital corners are the best way to ensure they are tucked in on the base.
Flat sheets are more versatile because one can use them either on the top or the bottom , subject to if they have a border design on them.
Fitted sheets are a pain to iron if you prefer a more professional look, and who doesn't?
Make sure you measure your bed mattress to ensure you get the correct size as there's so many variations with bed sizings and that of sheets that fit.
All the best