Welcome to the forum!
Any burn program such as Nero or Roxio (and maybe a free option such as CDBurnerXP?) will offer a format/erase function. In Nero for example, go to the Recorder menu, then choose Erase Disc...you can then pick from a quick or full format/erase, I'd recommend Full.
As Whappo says, only RW discs would need formatting. DVD-R, as in your thread title, does not need formatting prior to use.
If you are wanting to format a RW for use on a DVD recorder, the question of make/model is an important one, as my own Philips DVD recorder (DVDR-5500) freezes up completely when I try to use a disc which has been formatted on a PC (the manual even says not to use discs that have been used on a PC).