Chosen Solution

can we add any hdd in acer aspire r13?

You can not, because there is no 2.5" slot. It’s a M.2, mSata or equivalent (I’m not sure of which) so you can only add a different SSD with the same connector. There could be two slots and only one SSD but I’m not sure either. For further information about which type of SSD you could use and if there is a second slot available you better should contact Acer technical support (also to know guarantee condition about SSD adding/changing). edit : I’va checked and there are two slot in the R13 but I can not find which type they are. edit2 : and finally i found it, it’s a m.2 slot : review here