Before you leave
- Don't cancel the old hosting before the end: your site must stay online there during the move.
- Check the new server: a PHP version at least equal to today's, enough space, and its file upload limit.
- Locate your email. If your mailboxes are with the old host, they don't move with the site: plan for them separately.
- Make a full backup, and keep it off both servers.
The steps
- At the new host, install a blank WordPress.
- Transfer your site: back it up at the old host, then restore the backup at the new one.
- Check the site at the new host: pages, images, forms, admin area.
- Point your domain name at the new hosting, with the company you bought it from.
- Wait for the change to propagate, a few hours, sometimes up to two days, then check again.
- Keep the old hosting for a few more days, to be sure.
The domain name, last of all
It's the only step your visitors see. Only change the address the site points to; if your email is elsewhere, leave its settings as they are. And check that the https certificate is in place at the new host: without it, browsers warn your visitors.