I just started to know whether to invite people to dinner by phone or text.

when we first met, we wanted to invite you to dinner. For such a move, it should be better to make a phone call. We can communicate well on the phone, but we need to invite you to dinner. Are there other people here, or where are you invited to dinner? When these are very easy to communicate on the phone, it is also a kind of respect for the other party. If you send a text message, when the other party sees it, it is possible that he feels that you are not necessarily sincere, because as a text message, there is a difference between them and a phone call. Telephone communication means that some direct information can be done or not, so I still agree with you to call and explain all the things you want to do.