Hi this my first time posting on this site... I have up on the second floor a 2 30amp fuse sub panel that control 60% of the electrical on the apartment. How do I convert the fuse box to a Ciruit Box? Can I do it myself or should I hired an license electrician and how much will it cost? Thanks you...

Before trying to do this yourself, since you mention "apartment", most states do not allow DIY'ers to do their own electrical work in multi-family dwellings, along with insurance companies.

Replacing a fuse box to breakers is fairly easy for those that are qualified and knowledgeable of wiring, panels, etc.

Only you can tell us if you have the ability to replace the panel. Quite frankly, if you need to ask how, then that is another reason to hire a pro.

As far as cost, this is difficult to speculate, depends on the market your located in. Rural Idaho will be much cheaper than downtown Boston. Also depends on the types of materials needed, and the type of construction involved.

Sorry not much help, but that is the best I can provide at this time based on the info available.