QuickFile’s functionality allows you to record your expenses, income etc and prepare the required reports and figures for HMRC, Companies House etc. (among other things)
In terms of forward planning (cashflow forecasting for example), we don’t have the functionality for this at the moment. However, there is a lengthy topic on this that you may wish to look at (and add your vote to if you wish).
Perhaps you could use purchase orders, even if you don’t send them, but use them to enter details and then convert them to a purchase invoice when the actual invoice arrives? That way you would have a record of it, and you can see what’s outstanding.