IF Clause Type 1

Form
if + Simple Present, will-Future

Example: If I find her address, I will send her an invitation.

The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Example: I will send her an invitation if I find her address.

Note: Main clause and / or if clause might be negative. See Simple Present und will-Future on how to form negative sentences.

Example: If I don’t see him this afternoon, I will phone him in the evening.

Use
Conditional Sentences Type I refer to the future. An action in the future will only happen if a certain condition is fulfilled by that time. We don't know for sure whether the condition actually will be fulfilled or not, but the conditions seems rather realistic – so we think it is likely to happen.

Example: If I find her address, I’ll send her an invitation.

I want to send an invitation to a friend. I just have to find her address. I am quite sure, however, that I will find it.

Example: If John has the money, he will buy a Ferrari.

I know John very well and I know that he earns a lot of money and that he loves Ferraris. So I think it is very likely that sooner or later he will have the money to buy a Ferrari.

SOURCE:http://www.ego4u.com/en/cram-up/grammar/conditional-sentences/type-1