Conditional Sentence Type 1
→ It is possible and also very likely that the condition will be fulfilled.
Form: if + Simple Present, + Future (will/won`t + Infinitive)
Example: If I find her address, I’ll send her an invitation.
Conditional Sentence Type 2
→ It is possible but very unlikely, that the condition will be fulfilled.
Form: if + Simple Past + Conditional I (= would/wouldn´t + Infinitive)
Example: If I found her address, I would send her an invitation.