I am making a cleric with the magic initiate feat, and I took True Strike as a cantrip. Do I add proficiency to the attack roll?

I am wanting to attack with a quarterstaff that I have proficiency with, so do I add my +3 wisdom mod and +2 proficiency bonus for the attack roll?

Yes, you're right.

And True Strike requires in fact to use a weapon with which you have proficiency, according to the spell components.

Components: S, M (a weapon with which you have proficiency and that is worth 1+ CP)

There is a related thread here: Does True Strike (2024) substitutes the Weapon Proficiency needed for weapon usage?

Quote from Dumboy16 >>

I am making a cleric with the magic initiate feat, and I took True Strike as a cantrip. Do I add proficiency to the attack roll?

I am wanting to attack with a quarterstaff that I have proficiency with, so do I add my +3 wisdom mod and +2 proficiency bonus for the attack roll?

Yes. Basically, you're replacing the normal ability modifier you'd use for the weapon attack (Strength, in the case of a Quarterstaff) with your spellcasting ability modifier (Wisdom, if you're a Cleric). So in your case the attack bonus would be +5.