If you right click on an item in your junk mail folder, most e-mail programs put up an option to say "not junk". It may also ask if you want to specify the sender as safe.
How it works on your e-mail depends on which one you are using - they are all a bit different.
I am starting to think, that I will never be old enough--------to know better.
Tolerance will reach such a level that intelligent people will be banned from thinking so as not to offend the imbeciles. Fyodor Mikhailovich Dostoevsky, Russian Novelist
S.E. Mich. Flagstaff 26FKWS / 2022 F-150 3.5 EcoBoost SCrew Propride
Also check to see if you have a third party spam filter such as the Norton Security. If so, you may need to tweak it as well.
What email client are you using? (web, outlook, thunderbird, etc.) As other have stated, it depends on what you are using on how you would fix it.