mailto: using outlook 365

Hi,

Our business is in the process of upgrading staff to Office 365, including the web version of Outlook 365.

We have a few forms which are created using excel or Word and have buttons for which the vba code uses mailto to create an email to send the form as an attachment.

Some staff are now using Outlook 365 and these button presses no longer work as they cannot locate Outlook as they no longer have the program on their workstations with 365.

Is there a solution to this or will staff need to use an alternative method ?

Thanks