If you have an Office 365 for business or education account, you can use OWA for iPhone and OWA for iPad to access your email, calendar, and contacts.
When you want to see your email signature on your iOS device, you have to use these apps provided by Microsoft.
You can install it directly from the App Store:
'OWA for iPhone'.
'OWA for iPad'.
Why use OWA for iPhone and OWA for iPad?
OWA for iPhone and OWA for iPad support offline access to your email, calendar, and contacts.
The most recent items are downloaded to your device every time you use the app while online.
While offline, you can read and respond to downloaded messages and meeting requests. You can also create new messages, calendar items, and contacts.
When you first install the app, you will see Setting up this app to work offline. This may take a few minutes at the bottom of the screen.
Next you will see This app is ready to use offline. From then on, every time you use the app while you’re online, it will update the offline information.
The OWA for iPhone or OWA for iPad icon on your home screen will show a count of unseen messages.
You can use the options in OWA for iPhone or OWA for iPad to use Outlook on the web email signature when you send messages from that device.
To use Outlook on the web email signature, tap the more icon More options > Options > Email signature.
How do I install OWA for iPhone or OWA for iPad?
Go to the Apple App Store or iTunes on your iPhone or iPad and install OWA for iPhone or OWA for iPad.
After installing from the App Store, you will see the OWA app on your device.
When you first launch the app, you’ll be asked to enter your Office 365 name and password, which are then stored on your device.
Options on iOS device
To use Options on a mobile device, tap the navigation icon Navigation, then the gear icon settings .
After you've made the changes you want, tap the checkmark to save your changes and close Options.
To cancel your changes, tap away from the options page.
When you've created an email signature in Outlook on the web, you’ll see the Plain Text version here.
Only the Plain Text version can be used, so make sure you create a Plain Text version of your HTML email signature.