How do you file bugs?

If you are too lazy to read, then please just go to the comments and answer the question in the title.

Every company I worked for had its own rules for formalizing and reporting discovered bugs. Most often, there were no rules. What the tester found, he wrote down in the comments to the task (and that's still good!), and sometimes he just discussed it with the developer on a call, who quickly fixed it and the fact of the bug being found remained between them. For small studios, working like this may be acceptable, but sooner or later the lack of basic order starts to get annoying. And that's where questions arise, which each company tries to answer in its own way.

1. How to file a bug? A comment to the task? A separate task? A checklist in the task description?

2. How do I mark a bug as fixed? Verified? Recurring?

3. Which bug tracking system did you find most convenient? Jira? Youtrack? Yandex.Tracker? Bitrix24? Something from the newfangled import substitution?

4. What bug description templates are accepted in your company? No rules? Step 1 – step 2 – step 3 – expectation – reality? Screenshot with arrows? Video recording from the screen?

5. Is there any classification of bugs? Minor/major? Back/front? Backlog/critical?

I am very interested in your experience in this topic. I would be very grateful if you share your knowledge in the comments.