I need a safe way for the insurer and the claim adjuster to comunicate online

page 1. Login page: Fields will be username, password and claim number page 2. Administrator page: will have the ability to create/delete users fields for funcionality would be first name, last name, company name, username, password, email and if he is an adjuster or insurer. will also have the ability to create claims fields for funcionality will be claim number, insured name, address, phone number, date of loss, insurance company, adjuster, policy limits and deductable. page3 view claim and comunicate on claim: this will display the information on the claim as well as keep a record of comunications between the insurer and claim adjuster that cannot be altered or deleted.