You can create a secure share link for your project to share with your colleagues. Here's how this works:
Step 1: Open the project and click on the ( i ) button in the top bar, then select Project Properties from the menu.
Step 2: At the bottom of the first tab, check the box that says Link to Share.
You can then copy this link and paste it into the channel of your choice, for instance an email or a Slack channel.
If the link has fallen into the wrong hands, you can generate a new link anytime. The old link will become invalid and only people with the new link will be able to access the project.