Question about Missionary phones and other electronics

I understand that missionaries spend much of their time proselyting on social media.  I know they have phones, but are elders/sisters allowed laptops or tablets?  I can’t imagine having a very productive social media and web presence from just a small screen phone.  Are personal laptops or tablets allowed?  I do see missionaries from time to time, and all seem to have backpacks or messenger bags, so I’m wondering if they are carrying computers. 

I know this is a lot of questions, so thanks for any responses in advance!