Online forms are real challenge these days for reliability and mobile friendly use etc.
I would strongly recommend the use of a 3rd party software as a service form tool instead of the various free and paid WordPress form plugins available.
The reason being there are a lot of emails sent from within website that never make it to your inbox. It could be the hosting but I’ve seen it happen on $20 per month to $500 per month hosting plans equally. Sending email is also using a lot of resources and gets in the way of what you want your website to do the most and that is deliver the content to people quickly.
Anyway I have done a short video and blog post on this website about the subject so I suggest you click here to read more about why online forms suck.