is that ok to use 10w charger for iphone 6s for all the time i want to charge it any damage to battery life?

Using the 10w charger is fine, there won't be any battery damage as a result.

According to Apple themselves, it's perfectly fine to use an iPad charger (10w or 12w) with your iPhone.

Using iPad power adapters with your iPhone, iPad, and iPod - Apple Support

spsingh7007 wrote:

So can I charge my phone with 10w charger on daily basis ?

Yes, that is what I said.

You're welcome.