This is the 6th most frequent Catalan word.
ha
"Ha" is the third-person singular present indicative form of "haver," used as an auxiliary verb meaning "has."
In this sentence, the word 'ha' is part of the construction 'ha de', which expresses obligation or necessity, equivalent to 'has to' in English.
Ha d'estudiar per a l'examen demà .
They/she/he has to study for the exam tomorrow.
Here, 'ha' is used again in the present perfect tense, this time with the verb 'estar' (to be), forming 'ha estat' (has been) to refer to a completed action with present relevance.
Ha estat un plaer parlar amb tu.
It has been a pleasure to talk with you.
The word 'ha' is used as part of the present perfect tense, indicating an action that has occurred in the past but has relevance to the present. The auxiliary verb 'ha' (has) is paired with the past participle 'plogut' (rained).