On VRoid Mobile, you can call up and take photos of characters registered on VRoid Hub.
Once you have created a character with VRoid Mobile, tap the camera icon on the bottom right to select the location you want to shoot at and tap Shoot Alone. (You can't change your character in the Shoot Together mode)
When you tap the icon 
at the top right of the screen, the characters registered on VRoid Hub will be displayed at the bottom of the screen. Choose any character.
*Characters with age restrictions (R15, R18) will not be displayed.