You can add items to a proposal when creating the proposal or when editing an existing proposal. If you are using approval rules, changing a proposal can send the proposal through the approval process again.
To add items to a proposal, click the Items tab.
Click the Add Items button. This opens the Add Items popup, which shows the items that you can select.
Select the checkbox to the left of each item to add.
Click the Add Items button at the bottom of the popup.
To edit item details, click the item row in the Items grid. This opens the Edit Proposal Item form: