Supposed that you have successfully connected to the remote computer over AnyViewer, you are able to change the resolution to the one that you need.  Go to controller toolbar dnd click Screen. Then, you can see the offered resolutions for you to choose from. 



The maximum resolution that can be chosen is the maximum resolution supported by the host computer. For example, if the maximum resolution of the host PC is  3840 x 2400, then 3840 x 2400 is the maximum resolution that can be selected.
It's recommended to choose the proper resolution based on the network speed and computer configuration. The higher the resolution you choose, the faster the network speed and the higher the computer configuration that the computer needs.
 If you don't know how to choose resolution, you can click Adpative and the resolution will be adjusted automatically to maximize the usage on your screen.