I have
you have
he has
she has
...
had = past simple of the verb have
I have English lessons on Friday. ( I have ) Present tense .
Kris has English lessons on Friday. (Has ) Present simple tense
Kris had a English lesson on Friday. (had) Is used because its pass tense .
Sometimes "has" refers to a long-term trend whereas "had" refers to a single incident.