Mail icon doesnt tell me

I cannot find the right answer to my problem will saw 1 in this forum. but my phone doesnt have the options goto settings then general then Mail then something about undocking. theres nothing in any settings about docking or undocking

since i got my new iphone 8 plus my mail icon doesnt not let me know when i received a email no red 1 or no chime when i receieve an email..

Please someone give me steps by steps how to fix this i have checked every place in settings and there is no settings when i click on the mail icon either...

i have to click on the mail icon to see if i have gotton any sometimes i have to use thunderbird on my computer to check my emails.

Please help

thanks

Jon