You can request your availability, but you might not get shift. So don't count on this job as income source. Just for your experience.
They will call you day and night about the client's file you have and you've done.
Training is mostly online and company will ask you to file real tax... without OJT training. H&R Block's business is not doing well, they cut the cost for training.
Usually your office manager is new too. No one want to be Manager to deal with office staff, so company put new hired as Office Manager. Next year, the manager is not coming back.
No one will teach you how to deal with clients or question you have. Senior staff in your office won't help you, because they are busy. And helping you doesn't make money.
Don't accept the role as Customer Service Leader or Office Manager. You are ending up used like slave by Senior staff. When you have problem with senior staff, your District Manager won't help you. They will pick Senior staff, not you.