okay so i am trying to make a weapon (Mace of the Necromancer) it dose normal damage but adds 1d4 necrotic damage but i cant seem to put in under stats.... can someone help

What do you mean by stats? If you just want it to deal damage. Do this: Create Magic Item > Weapon > Flail add the descriptors for your weapon and such like (Requires Attunement)

Then for adding the 1d4 necrotic damage. Do this: Go down to Modifier in the Weapon Editing Page > Modifier > Select Damage > Necrotic > Dice Roll 1d4 > save > Save in the main editing page of the weapon and click the blue save button twice.

Wait for 5 - 20 minutes for your weapon to fully register in dnd beyond. There Mace of the Necromancer. Also go to Homebrew Magic Item Creation in the Forums you can search how to make Magic Items there.

Here is an example how to add damage to a weapon or make a weapon that deals that kind of damage.

Modifier: Damage->Subtype: Necrotic->Dice Count: 1->Die Type: d4

Note, the character sheet won’t roll that additional damage automatically yet, you will still have to roll that 1d4 manually.

Late but if you have beyond 20 you can click on the d4 as it will highlight in the magic item.

Quote from Lolths_Bane >>

Late but if you have beyond 20 you can click on the d4 as it will highlight in the magic item.

 Thank you. I am aware, but I don’t use Beyond20, I just use DDB. (I personally hate VTTs, if I wanted animation I’d play a video game. I play D&D to use my brain, including ToTM play style. I even resent the animated dice on the DDB character sheet.