Is there a way to share the total numbers of hours I plan to spend on a project?

There are two ways to achieve this:

1. You can see the total hours planned for a project in the Project view -> Progress overview tab. This is available on all paid plans.

2. You can set up a project estimate that signifies the total time estimate for the entire project in hours. This will be taken into account under Project Overview, and it helps to keep an eye on the initial estimation, comparing it against task estimations that get added and updated as the project progresses.