1. I'm getting dressed to go to school.

2. I'm getting dressed for school.
3. I'm putting on clothes for school.
4. I'm wearing clothes for school.
5. I'm putting on clothes to go school.
6. I'm wearing clothes to go school.
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Which ones are grammatical? Are they all grammatical? Then, which ones are commonly used?

All are correct. All would be used. 4 and 6 mean something slightly different than the others. I'm wearing means I already have the clothes on, I'm not in the process of getting dressed or changing clothes.