Programs designed to perform specific tasks for users.

Packaged software

Term used to describe software that is bunched together making a complete set.

Example :
-Microsoft Office includes many software programs that may be used in the office, such as Microsoft Excel, Microsoft Word and Microsoft Access.

Custom software

(also known as Bespoke software) is a type of software that is developed either for a specific organization or function that differs from or is opposite of other already available software (also called off-the-shelf or COTS software). It is generally not targeted to the mass market, but usually created for companies, business entities, and organizations. Custom software is also when companies or governments pay for customized software for budget or project managing.
Examples of bespoke software include commercial products such as commercial websites, business databases and software for governments. Non-commercial custom software development is common in academic and open source circles.

Example :
- UBS (User Business System)
functions : accounting, payroll and stock & billing

Shareware

Shareware is usually offered as a trial version with certain features only available after the licence is purchased, or as a full version, but for a trial period. Once the trial period has passed the program will not run until a licence is purchased. Shareware is often offered without support, updates, or help menus, which only become available with the purchase of a licence. The words "free trial", "trial version" are indicative of shareware.
The term shareware is used in contrast to, retail software which refers to commercial software available only with the purchase of a licence which may not be copied for others

Example :

-Registry Mechanic® 8 for Windows® - New Version
Registry Mechanic InformationCurrent Version: 8.0.0.900
File Size: 7,339 KB
Operating System: Designed for Windows® Vista™ (32-bit and 64-bit), 2000 and XP.
Release Date: January 14, 2009
Designed to: Clean, defrag and compact your registry to optimize your PC for better performance.
Trial Limitations: The trial is time unlimited and removes problems found in 6 sections of the registry only.
A registered version is required to remove all detected problems.

Freeware

Freeware is computer software that is available for use with no cost or for an optional fee. Freeware is often made available in a binary-only, proprietary form, thus making it distinct from free software. Freeware allows authors to contribute something for the benefit of the community, while at the same time allowing them to retain control of the source code, future direction of development and preserve its business potential. Freeware is different from shareware, where the user is obliged to pay (e.g. after some trial period or for additional functionality).

Example:
-AVG Anti-Virus Free Edition 8.0.176

Not rated Average User Rating: 4.0 stars (out of 17362 votes)
Downloads: 156,788,403
Requirements: Windows 2000/XP/Vista
Limitations: No limitations
Date Added: January 05, 2009

Public domain software

Public domain software is software that is not copyrighted. If the source code is in the public domain, that is a special case of non-copylefted free software, which means that some copies or modified versions may not be free at all.
In some cases, an executable program can be in the public domain but the source code is not available. This is not free software, because free software requires accessibility of source code. Meanwhile, most free software is not in the public domain; it is copyrighted, and the copyright holders have legally given permission for everyone to use it in freedom, using a free software license.
Sometimes people use the term "public domain" in a loose fashion to mean "free" or "available gratis." However, "public domain" is a legal term and means, precisely, "not copyrighted". For clarity, the Free Software Foundation recommends using "public domain" for that meaning only, and using other terms to convey the other meanings.

Example :
- Linux OS
Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world.