If an adder is not showing on a proposal, first check to make sure it is active. An org admin can do so by clicking Settings > Pricing > Adders. The Status column will show if an adder is active or a draft.
If the adder is active but not showing, check to make sure it is attached to the pricing model being used by the deal template or authorized dealer.
Click Settings > Pricing > Pricing Models and click into the pricing model being used on the deal template. Next, make sure the adder has been added to the pricing model in the adder box.
Check that the pricing model is attached to the deal type being used under deal templates. If the pricing model is not attached to the deal template, the adder will not show.
If the adder is added on the proposal but shows "did not activate", the adder has custom pricing set up that only allows the adder to activate when certain conditions are met.