You can ride indoors using either a stationary bike or a regular muscle‑powered bicycle. An electric‑assist bike has no real purpose on a home trainer. I won’t provide guidance on stationary bikes, as I have no personal experience with them.
Whatever bike you use — mountain bike, road bike, or gravel (the budget varies) — choose a model with 26‑ to 29‑inch wheels, equipped with either a quick‑release skewer or a thru‑axle. Just make sure your bike is compatible with your home trainer (type of axle, cassette, or trainer‑specific tire depending on the model).
Indoor bike example
Road bike example