If you have a meeting you need to attend (no "to" at the end), then you are simply expected to be AT the meeting. If you have a meeting (or anything else) to attend TO, that means it needs your attention, you have to do something, set something up, prepare for it in some way, etc. Attend: Be at Attend to: Take care of
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.