Hello MUPPAVARAPU, SRAVANI,
Thank you for posting your query in the Microsoft Q&A Community.
I understand that you would like to get the list of users with Global Administrator role to assign roles on the Subscription in your tenant.
If you have access to the Entra ID of the tenant, you can go to the Global Administrator role under the Roles and Administrators blade.
Alternatively, you can run the Cli command below to get the Principal Id of these users with Global Admin role.
az login
az rest --method get --url "https://graph.microsoft.com/v1.0/roleManagement/directory/roleAssignments?$filter=roleDefinitionId eq '62e90394-69f5-4237-9190-012177145e10'"
NB: You need to elevate the Global Administrator access before the account can manage the roles on the subscription.
Follow the link to steps involved in elevating access of a Global Admin account
Let me know if further assistance is needed.
Babafemi