Shareware and freeware are two terms used in referring to different software. The first major difference between them is that the freeware is totally free to use for as long as you want to use it; while shareware is not absolutely free, you will need to later pay a certain amount to be able to continue using it and to also maximize the usage.
Shareware can be made freely and fully available when you become a registered user, or it will be fully and freely available for some first moment of usage, after which you will need to pay some amount of money to continue using the package. This is not so for freeware as it has no restrictions, and you will simply get what you see.
However, until the time you register your shareware, you can share it with others; but immediately you register it, you will not be able to share with others. On the contrary, this is not so for freeware, as it is available to share anytime.