Typically taxed as "taxable grants"--aka you need to pay income tax but not necessarily payroll taxes (social security and medicare). "Educational expenses" are things like tuition and textbooks and things which you probably won't actually pay for. (Also they're not straight deductions, they're calculated as a fraction, etc, etc, it's complicated; you'll almost certainly take the standard deduction instead) I get a W2 from my program but conceivably you could get a 1099G as well--depends on whether payroll classifies you as an employee or something else.
Most MSTP programs will withhold taxes for you and then when you fill out your return, well exactly a year from now, you'll figure out if it was too high (most likely) or too low (unlikely), so you can ask your program approximately how much they withhold per month to get an idea of your after tax income.
The one thing you will get to deduct straight off is moving expenses if you move >100mi so keep all your receipts if you hire a mover! Also if you'll have to file taxes in two states (moving from a job to MSTP) make sure you prepare for that.
As you may be able to tell, I just did my taxes lol, so if you have any questions feel free to PM me.
