"To take necessary action" means to do what is required or needed in a situation to resolve a problem or achieve a goal. It suggests that one should take the appropriate steps or measures to address an issue effectively. Full definition
After reading the main reason which are responsible for your huge car insurance bill every month, you should take necessary actions in order to reduce the high premium rates for your vehicle insurance. (autoinsuranceinvest.net)
The present British Government is now convinced of the necessity of building new nuclear power stations, but is failing to take the necessary action for fear of losing votes. (faith.org.uk)
If your landlord has placed this requirement in your rental lease, then be sure to take the necessary action of securing a policy as soon as possible. (rentersinsurance.net)