There is a lot of overlap between online giving and mobile giving. Both types of giving accept donations from digital channels, such as online donation forms, emails, and social media sites. The difference between the two is the device being given from. Online giving is done from a computer, while mobile giving is done from a mobile device like a tablet or smartphone.
So, if you were donating to an organization after viewing an email on your computer, it would be online giving. If you took the same action from your smartphone, it would be mobile giving.