“I am” is correct and the right conjugation of the first person singular of the verb “to be”. “I is” is incorrect and should not be used in English.
We use “I am” when we want to use the verb “to be”. We often use the verb “to be” when we want to describe our state of being.
I am tired.
I am happy
I am fixated on this.
We also use “I am” with verb tenses like the present continuous.
I am playing football.
I am trying to open the bottle.
I am going to the shops later.
The full conjugation of the verb to be in the present is:
We don’t use “I is” as a conjugation of the verb “to be”. There are people who use “I is” in some parts of the United States and England.
I is from Texas.
If you are a student learning English, I would advise against using this form of English.
There is however a situation where you can use “I is”.
We can use “I is” when you are talking about the letter “I”.
“I” is the third vowel in the alphabet.
“I” is the first-person pronoun.
For most situations “I am” is correct”. Only when you are talking about the letter “i” will you need to use “I is”.