To assist future clients getting clarity on you as a supplier it is helpful to get reviews and ratings from your current clients.
We would suggest you contact them with links to the review page and ask them to rate your business. An example email is shown below, please customise and use it as you wish.
As a valued client I wanted to write and ask if you would give some feedback and rank our business on a new website outsource.dev for B2B outsourcing which will help us and future clients.