R discs are recordable, once and RW disc are erasable and can be reused. The + or - don't seem to be an issue now except for the DVD+R/DL [Dual-Layer] discs which have a capacity of about 8GB versus about 4.3GB of the others. Used to be burners could do only + or - but the last several years have merged the 2 types [think back to the BETA tapes versus VHS tapes where VHS won out].
DVD-R and DVD+R don't usually need formatting, gets done 'on the fly' when recording or copying. DVD-RW and DVD+RW usually do need it but prompts will come up. Some burning programs can cause an R disc to be used similar to a USB device.
I'd use the free CDBurnerXP to check the discs and drive/s.
https://www.cdburnerxp.se
Or this free one:
www.nch.com.au/burn
I have the first one on a couple of computers, works good.