arc42 is a template for architecture communication and documentation.
arc42 answers the following two questions in a pragmatic way, but can be tailored to your specific needs:
One. What should we document/communicate about our architecture?
Two. How should we document/communicate?

• 1. Introduction and goals: Requirements, stakeholder, (top) quality goals
• 2. Constraints: Technical and organizational constraints, conventions
• 3. Context and scope: Business and technical context, external interfaces
• 4. Solution strategy: Fundamental solution decisions and ideas
• 5. Building block view: Abstractions of source code, black-/whiteboxes
• 6. Runtime view: Runtime scenarios: How do building blocks interact
• 7. Deployment view: Hardware and technical infrastructure, deployment
• 8. Crosscutting concepts: Recurring solution approaches and patterns
• 9. Architecture decisions: Important decisions
• 10. Quality: Quality tree and quality scenarios
• 11. Risks and technical debt: Known problems, risks and technical debt
• 12. Glossary: Definitions of important business and technical terms

• Use activity diagrams with swimlanes to describe or specify runtime scenarios

• [Describe the solution approaches as a table!] (https://docs.arc42.org/tips/4-2/)

  • quality goal: What’s the top-level goal?
  • scenario: What is a or the detailed scenario for this quality goal?
  • solution approach: How does the system approach this scenario? What tactics, approaches or decisions have been taken in this direction?
  • link to details: Where are the details of this solution described? This link will either point to a concrete building block, (implementing the approach) or a section of the crosscutting concepts.

• Document the various environments

• Use sequence diagrams to describe or specify runtime scenarios

• collection from arc42 as checklist for concepts

• mind-map as quality tree

• Document and explain the specific quality tree

• quality tree as checklist

• Amend the glossary by a (graphical) model

• https://docs.arc42.org/home/
• https://arc42.org/overview/