UML activity diagram - User registration

"A registered user is one who uses a program or a website and provides his/ her credentials, effectively proving his/ her identity. ...
Generally speaking, any person can become a registered user by providing some credentials, usually in the form of a username (or email) and password. After that, one can access information and privileges unavailable to non-registered users, usually referred to simply as guests. The action of providing the proper credentials for a website is called logging in, or signing in." [Registered user. Wikipedia]
The UML activity diagram example "User registration" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"A credit card is a payment card issued to users as a system of payment. It allows the cardholder to pay for goods and services based on the holder's promise to pay for them. The issuer of the card creates a revolving account and grants a line of credit to the consumer (or the user) from which the user can borrow money for payment to a merchant or as a cash advance to the user." [Credit card. Wikipedia]
The UML component diagram example "Credit card agency" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"The most common issue tracking system's design is relatively simple. A database is the main storage repository for all data. The data is managed by the business logic layer of the application. This layer gives the underlying raw data more structure and meaning, preparing it for human consumption. The now human readable data are then presented to the support technician by another software application or web page. The end-user of the issue tracking system can create entirely new issues, read existing issues, add details to existing issues, or resolve an issue. When a user of the system makes a change, the issue tracking system will record the action and who made it, so as to maintain a history of the actions taken. Each user of the system may have issues assigned to them, that is, that user is responsible for the proper resolution of that issue. This is generally presented to the user in a list format. The user may have the option of re-assigning an issue to another user, if needed. For security, an issue tracking system will authenticate its users before allowing access to the systems." [Issue tracking system. Wikipedia]
The UML communication diagram example "Ticket processing system" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.