Bring HTML web resource in CRM 2015 tablets and their limitations

Limitation of CRM 2015 tablets

Initially available for CRM Online only
iOS and Android tablets only (no Windows based devices)
No pop-ups from an iFrame or web resource
No authentication for embedded Office 365 sites
Could cause instability in the client
No Silverlight and image web resources
You can see the full article regarding all limitations here.

If you want to display the HTML page in CRM tablets.There are three steps.
1.Enable web resource in system setting
2.Check crm for tablets in web resource
3.Check CRM for tablets in form webresource properties.

If you have a scenario where this could work for your organization you’ll need to enable the feature under Settings -> Administration -> System Settings and then navigate to the Customizations tab.

Web Resources
If you’re going to want to use one of the supported types of web resources you’ll also need to enable it for the tablet client. You can do this by opening the web resource from the Customizations area and making sure the ‘CRM for tablets’ option is checked.

Once you’ve added the web resource to the form the last step is to check the ‘CRM for tablets’ option on the properties.

Here is a screenshot from an Apple iPad.

iFrames
If you are looking to use an iFrame should remember to use a HTTPS URL in order for it to show up correctly in the supported tablet clients. Like web resources you will also need to enable it to be displayed on the properties.