Can i charge my i phone 7 plis with 10 w fast charging adapter? Does it effect on battery?

1. 10 watts will not fast charge an iPhone.
2. An iPhone 7 does not support fast charging.
3. No. You cannot damage the battery by charging.
4. See here for Fast Charging details: link-> Fast charge your iPhone - Apple Support

The iPhone 7 does not support fast charging. While you can use the 10w power adapter, it will not charge the phone any faster. The phone will only use what power it can for charging.