The simplest way is to have your client add you as a creative manager (or higher) on their ads account and then submit the Lens through the Business Lens submission process.
If that is not an option, you can share the publishing link to let your client publish the Lens without needing Lens Studio or the project file:
- Open your project in Lens Studio and press the Publish Lens button.
- At the pre-submit page, copy the URL and share it with your client. Note:this link is good for 24 hours
- Have your client follow the link and sign into the account they want to publish from. They will be taken to a page verifying what account they are about to publish from.
- Once they click Submit with this account they will will be taken to the pre-submit page and can submit the Lens through the normal publishing workflow.