This isn’t functionality available natively in Asana.
There are several time tracking applications that include invoicing based on time logged. I’m not familiar with each and every one of these, but several include the ability to specify unique rates per task / per person / per project / per client, as well as support fixed-fee projects. From my personal experience, Harvest and Everhour appear to be good potential options, but do check the full list for yourself as the capabilities available from the add-ons is constantly improving.
I have in the past experimented with the following options in Asana for invoices based on time/quantity which might be useful ideas for you to explore further:
- Add a Fees custom field and maintain this manually. This works best if you have fixed-fee work, or if you’re happy to cost up high-level activities (and then perhaps put the more detailed tasks as subtasks).
- At the end of each invoice period I look for tasks completed and export the data into Excel/Google Sheets and then into my invoicing tool.
- Add a Service Type and Quantity fields or something similar (I had ServiceType and Hours in my scenario) for tasks that can be invoiced and configure these manually.
- At the end of each invoice period I look for tasks completed and export the data into Excel/Google Sheets.
- If you need to manipulate the data (e.g. look up the appropriate rate and then multiple by hours to get the actual fees) you can do so in Excel/Google Sheets. In my case I was able to carefully configure the ServiceType field so that the ServiceType and Hours data could be pasted directly from Excel into my invoicing tool which would then apply the correct rates.
Both these options required some effort to maintain and include a manual export step that may not be ideal. I found the time saved by working in Asana overall made up for this, but of course avoiding a manual export and having a tool pull the data directly would be preferred!