Once your aimbot has set your viewangles x and y to the enemies head vector, you can put this below:
or if you want it glowing:
Drawing.DrawString(40, 20, normalFont, 1.0f, colRed, pClient.Name);
Please note that this is 100% not c+p so if you don't know what to do I advise you personally to read some books on c++. Also even download source codes that are all over the internet and study those.
sprintf(szTargetName,"Target: %s", pClient.Name);