Preparing a quote for the supply of goods or services is similar to preparing a sales order—in fact quotes and (unprocessed) sales orders are interchangeable.
To prepare a quote:
In the Transaction list, click the New button or press Ctrl-N/⌘-N
A new transaction window will open.
If necessary set the transaction Type to Quote
Pressing Alt-Shift-6/Ctrl-Shift-6 is a keyboard shortcut for this.