Upvoting everything is not a good idea. Steemit is designed for 20 upvotes a day. You could give up to 20 votes at full power and every vote over 20 would weaken the reward for all your votes. So voting for only the best content is better.
When you upvote someone's post, you are rewarding them with Steem Power (SP) and Steem Dollars (SBD) that will be newly created at the next scheduled payout. It does not come out of your SP.
gregory finally ,that was the answer i was looking for the whole day. Thanks man 🎉
Glad I could help.
This is very important and should be stickied somewhere.