If you have the app installed on your phone, just find it in the app list, long-press on it and select "share", then choose how you want to share it (email, SMS, Facebook, OneNote and so on).
If you don't have the app installed, open Store and find it there. If it's a free app, then tap the "share" button at the bottom. If it's a paid app, then expand the ...
Is Share option present in Groove
Yes there is a share option built into the Groove music player. But, the share option in Groove is a URL/link sharing option and not a file sharing option. Below is the changelog related to this option, when the feature arrived to Groove in version 3.6.2142
Copy links to songs, albums, and artists right in the app so you ...
You can share multiple photos in WhatsApp as follows:
Select the person with whom you want to share photos
Tap the "attach" icon
In "Attach media", tap "Photo" and select the album where the photos are
Tap "select" at the bottom to mark the photos which you want to share
Note: You can share a maximum of 10 photos at once).
Windows Phone 8.1 supports sharing the screen to Mircast devices (where the phone is compatible - not sure if the 620 is), or over USB to desktop PCs running the Project My Screen app.
I'm not aware of a phone acting as a Miracast receiver, so you might not be able to share screen from phone to phone