If you are often facing the iPhone email formatting problems on your iPhone, check if you have performed the correct steps to format the message. The procedure to check this is given below.
Gmail application - Email formatting:
Launch the Gmail application and tap the Compose icon at the bottom-right end of the screen.
Type the text message and double-tap the text that you need to format.
Choose your preferred format options.
Mail application :Signature formatting
On the home screen of your iPhone, tap the Mail option followed by the Signature option.