How to add an email account to my iPhone?

Ok so I’m not great with technology, but yesterday my mail (emails) failed to load, and today when I woke up all my mail was completely empty, so I did the whole search the internet for answers but non of them worked, so finally tried the delete account and re add it, mmm big mistake because i had to add things like host name??? Host address or somethings like that and I didn’t have a clue, it’s now saying couldn’t connect to server I have no idea to correct this and obviously really need to access my emails. Help please

[Re-Titled by Moderator]