Adjectives change, for masculine and feminine, and plural and singular.
I will capitalize what changes.
Yo soy gordO. (If I am a man, singular)
Yo soy gordA. (If I am a woman, singular)
NosotrOs somos gordOS. (Plural, men or a mix of men and women)
NosotrAs somos gordAS. (Plural, only women)
Feo (m) / Fea (f) and so on. This is the basic, and apply for most words, but not for everything.
You might find inclusive language. People are starting to use "e" to replace "o" (linked with masc) and "a" (linked with fem), Like this:
NosotrEs somos gordEs
There is a big debate about it right now