免费软件：
它是一种免费提供给用户的软件，具有无到期日的全功能机制。
Anyone can download it from the internet and use it for free.在此作者保留软件的版权。
共享软件：
它是一种商业软件，最初免费分发，但后来收费以保持功能继续访问。
It allows the people to “try before they buy”.| FREEWARE | SHAREWARE | |
| Cost | Free of cost | Free for specific period of time later on asked the user to purchase. |
| Modify source code | Not allowed covered all the copyrights. | Not allowed covered all the copyrights |
| Fully Functional | Usually | Certain features are provided for trial later on to unlock the rest features, users need to pay. |
| License and Copyright | All the copyright laws are retained. User License or EULA(End User License Agreement)is important to the user in order to access the freeware. |
Here also copyrights holders hold all the rights. Shareware is a more limited version and is also restricted by the license. Typically the license restricts the user from modifying, copying or distributing the shareware. After the designated trial period if the user wants to continue with the use, it is the infringement of copyright and may constitute piracy. |
| Features | All features are freely available | Some features are available for free trial or have limited use. To enable the rest features, payment should be made. |
| Distribution | Free of cost distributed among the people. | May or may not be freely distributed usually requires author’s permission. |
| Access Duration time | Having no time limit | Program may only work for short duration eg 30 days. |
| Advantage | A free copyrighted software | Some features are free for trial and covered by copyright. |
| Disadvantage | Neither can sell these software nor can make any changes | It cannot be modified and it may be either a cut down or a temporary version. |
| Examples | MSN messenger, yahoo messenger, Adobe PDF,etc. | Winzip,CuteFTP, Getright,etc. |
参考
https://www.computerscience.gcse.guru/theory/free-software-freeware-shareware
https://www.diffen.com/difference/Freeware_vs_Shareware