Mistakes on the site. How to fix it?

Recently faced with a problem when creating my own site. Please tell me what to do if my site gives out errors and what to do to fix them?

I also encountered this, but I was advised a service that gives you site analytics and shows you the errors you encounter. It's really convenient, clear and fast. If you follow this link and see the error, you'll immediately understand what you have to do to fix it. Here is a link to the service where you will find website error checker https://pr-cy.io/ So try the option I suggest

Hello. How can you get a digital product tailored? So, in my opinion, business marketing is a big term that includes digital marketing also. Business marketing refers to marketing your services with any of the methods, but on the other hand, digital marketing specifies only one direction of promotion, that is over the internet.

I don't think this is the best solution in this situation, there are alternatives