Yes, everyone has the ability to post on the team feed. However, the admin has the ability to edit the team settings to require approval of non-admin posts. In the event this setting is turned on, no other members will be notified of the post until it is approved by a team admin.
Admins can also adjust the settings to only allow only admins to post. In the event this setting is turned on, non admin will not be able to post to the team feed at all.
Non-admins can post to the team feed, however the admin has the option to require post approval or limit postings to only admins depending on the team needs.