Ok. Thanks for replying,
I was thinking 
if I download ubuntu supported 64bit i368 package and install after adding cross platform of i368 with "sudo dpkg --add-architecture i368" for the Anydesk " https://download.anydesk.com/linux/anydesk_5.5.6-1_amd64.deb "
Well I am not sure if it will work or not...
Actually why I wanted to install Anydesk is because it is simple to use and the Raspberry Pi is located 300 kilometres away in a small village from my location (Bangalore India). There my dad is using Raspberry Pi 4 4gb model running Ubuntu Mate 64bit 20.04lts as a desktop computer.
He is not much familiar with linux and I am supporting him over video call to do software installation. And all he got is a smartphone and Pi 4 at present COVID19 situation.
If anyone can suggest me any GUI based remote access application that can run on existing software it would be very helpful...
Thank you..