You will receive an offerwhen there is mutual interest between youand the coaching staff. This is an important and exciting moment for you but it will also change the recruiting process going forward..
There's a balance between waiting for other opportunities and closing the offer. Try to be patient and don't rush to commit until you've gotten a chance to really explore the school, the coaching staff, and the community. These are big decisions about your future, you owe it to take some time to make a decision.
Coaches recruit based on what they need to complete their team for the upcoming season. When looking at programs, you want to research the current roster to see their depth chart in your position. If you know how many athletes are in your role on the current roster and in the incoming recruiting class, you can start to get a sense of who has a spot to offer.
If you've explored your options and feel good about a school that has sent you an offer, you can give a verbal agreement at any time in the college recruiting process. Keep in mind that a verbal agreement is NOT binding, and if there is a coaching change or you have a career ending injury, a school does not have to honor the scholarship offer. Even though a verbal agreement is not binding, breaking the verbal agreement is frowned upon, so make sure you're sure before you verbally commit.
The earliest you can sign a National Letter of Intent (NLI) with a program is November of your senior year during the early signing period. Once you sign an NLI you are committed to that school and other schools can no longer recruit you.