Question

Difference between i wrote a letter and i have wrote a letter

Answer 1

i wrote a letter. mins>>>मैंने एक पत्र लिखा था

i have wrote a letter mins>>>
मैंने एक पत्र लिखा है

Answer 2

Dear friend, that's I have written a letter not 'wrote.'
I wrote letter means aapne letter likha and I have written a letter means you have just finished writing it. And then you are telling somebody.
When you will tell someone about it much later, you will say I wrote a letter.