How to you engrave your runeblade in WoW?

Answer 1

A starting death knight has the Runeforging Skill (found in the general tab of the spellbook, "P" button). When you get the quest to Emblazon a Runeblade, you simply walk to one of the weapon racks (they will have glowing sparkles around it) and right-click it to get an unadorned runeblade.

Then, walk to a forge, open your runeforging skill, click a rune and apply it. You have then completed the quest.

Any time you want to forge a new rune (on a new weapon for instance) follow the same process. You need to be close to a Runeforge to do so.

Answer 2

First, be a Death Knight. Second, go to the Death Knight area of Acherus: The Ebon Hold, on the lower level. There are Runeforges there, stand next to one. Next, open your spellbook, and find the Runeforging ability. This opens up a windows with all the runeforges that you have access to. Click on one, then the engrave button, then click on the weapon that you want to runeforge. There, you are done.