To access the phone you must have the menu bar displayed, where the options, saving, etc, appear.
The laptop, or any type of computer for that matter, will only appear if you have purchased it. Desktop computers will only be accessible in your bedroom, while laptop computers can also be used in the library or classrooms. Having a laptop will increase your studying in all of the places mentioned, as well as allowing you to access the internet in the library and in your bedroom. The desktop computer does exactly the same thing but only in your bedroom since you can't move it. As long as you are in your bedroom and have a laptop or desktop computer, you can also play a game. Note that the quality of the device plays a role, so a desktop computer inferior to a laptop will not be used, instead the laptop will always be used. Otherwise, the latter will only be accessible outside the bedroom since the desktop computer will be used inside it.
Also keep in mind that unless you are inside your bedroom, you will only be able to access your phone or laptop if you are carrying an object that can hold them. Backpacks or briefcases usually do the trick, and the phone can also be carried in smaller containers. There are phone-casses, and the dildo bandolier can also hold it.