Whether I should share my ideas with investor if not registered

To put it in simple words here are no IP rights for "ideas" per se. That said, there are multiple ways in which one can protect their creation. Trademark, copyright and patent registrations are the more conventional ways of securing IPR, subject to, of course, what specific registration is applicable to the business. With respect to trade secrets, there is no statutory protection. They are protected through contracts and, therefore, it is important to get full proof employment contracts drafted. It is also important to sign a NDA with all vendors. You should meet a start-up lawyer who can give you advice specific to your situation.