''IF I WILL.......'' or ''IF I..............''

Normally, it is ungrammatical to use the following sentences:

I will phone you IF I WILL have time.

You will find Coca-Cola WHEREVER YOU WILL go.

IF YOU WILL call me, I will attend the party.

IF THEY WILL go abroad, they will help me a lot.

These type of sentences are so common among many speakers of English in India due to the strong influence of mother tongues like Hindi, but they are not used by native English speakers. Rather, they use the follwing substitutes:

I will phone you IF I have time.

You will find Coca-Cola WHEREVER YOU go.

IF YOU call me, I will attend the party.

IF THEY go abroad, they will help me a lot.

The rule is that a present tense goes with IF (and most other conjuntions) to refer to the future.

However there are certain situations where we may use IF......WILL.
E.g.,

1. I will give you $ 100 IF IT WILL help you to get good medicine. (meaning IF IT WILL BE THE LATER RESULT)
2. We will go home IF IT WILL make you feel better. (meaning IF IT WILL BE THE LATER RESULT)

Compare these sentences with the following ones:

1. I will give you $ 100 IF I win the lottery. (this 'IF' stands for a condition, not a later result)
2. We will go home IF we get a car. (this 'IF' stands for a condition, not a later result)