The first scenario we want to walk through is sharing the Transit Gateway so that we can easily route between VPCs that are in other accounts but still in our organization. We can share outside of our organization too through invitations. In this case we are going to share with the organization.
In the AWS Management Console change to the region you plan to work in and change. This is in the upper right hand drop down menu.
Lets determine the scope of the share. If you are pairing up with someone, choose Option 1 below, we will use their Account number. If you are working in your Organization, you can also use Option 2 and share with all of the accounts in your AWS organization.
note: in order for organization sharing to work, you must change your Resource Access Manger Settings from the master account. login to the master account and change this setting as shown below.
In the AWS Management Console choose Services then select Resource Access Manager.
From the left-hand menu select Resource Shares (you may have to open the Burger menu). Click the Create a resource share button in the upper right of the main panel.
Fill out the Create Resource Share details:
Verify you have everything entered correctly and click the Create resource share in the bottom right of the main panel.