totemomail® - How To – Installing SMIME certificate on iPhone
You should receive an email with an attachment that ends in “.p12” as indicated below.
Click on the attachment and then on “close”
Go to “Settings” on the iPhone and then tap on the “Profile Downloaded”
Tap on “Install” as shown underneath.
Enter the passcode for your iPhone.
Select “Install”
Select “Install” again:
Enter the password that was provided to you.
This password may have been sent with the mail with the certificate attached or separately in another mail / WhatsAPP / SMS etc.
Select “Done”
Encrypted mail sent to you should now be readable on the iPhone and it should show that it is encrypted.