By default, only the New, Edit and Print buttons are available on the Documents list screen's sidebar. You may add the Posting and Delete buttons underneath the Print button:

oPosting - This will allow you to launch the Update ledger screen to update (post) documents (Invoices, Credit notes, Purchases and Supplier returns) to the ledger. 

If Quotes and Orders are selected as the document type, the caption of the Posting button, will change to Confirmation. If you click on the Confirmation button, it will launch the Confirm quotes and orders process option on the Documents list screen's context menu.

oDelete - This will allow you to delete an unposted document.

documents-add-no-post-delete-button

If the Posting and Delete buttons are not available, you may:

1.To post documents, click on the Update ledger (Action ribbon) or press the F3 key.

2.To delete documents, click on the Edit → Delete → Documents (Action ribbon). 

documents-delete-menu

To add the Posting and Delete buttons to the Document list screen:

1.On the Setup ribbon, select Access control.

2.Select the Documents tab. 

3.Select (tick) the "Document posting" field.

documents-add-post-button

4.Click on the Apply button.

5.Click on the Close button.

6.You need to click on Tools → Close active forms  (Setup ribbon) or reopen the Set of Books. The Delete and Print buttons will then be available on the "Document list" screen. 

documents-added-post-delete-button