Drop bar to flat bar conversion Gearing             14-Speed Shimano A070 STI
Crankset            Prowheel Ounce 42/52T Double Chainring Alloy Crankset
Shifters            Shimano A070 STI
Front Derailleur    Shimano Claris
Rear Derailleur     Shimano A070
Brakes              Tektro Dual-Pivot Caliper Brakes
Brake Levers        Shimano A070 STI

Above is what I currently have. I am looking to convert from drop bar to flat bar to use the bike as a casual fitness and commuter bike. All I know is that some parts are road bike specific and may need replacing if I want the conversion done. I hear that the front derailleur, shifters/brake levers (obviously since it currently has STI) and the bar it self. Is there anything else that needs to be changed? I would like someone who has more knowledge in bikes than me to possibly tell me what parts from the above mentioned list needs to be changed. I am not looking to do any upgrades. Just looking for cheap budget parts since it will just be a leisure bike.

Thank you all

Sincerely

Tom.
It's almost certainly going to be more cost effective to replace the whole bike, and selling the current one.

There are potential problems with both brake caliper and derailleur compatibility going to flat bar shifters.

Aside from replacing shifters, drivetrain and bar, drop bar road bikes have shorter frames than flat bar bikes, because the rider's hands are placed forward of the stem head on the drops or hoods, but a flat bar places them approximately level with stem head. You may find the seat to bar distance is too short with flat bar installed.