A desktop publishing application from Microsoft that focuses on page layout and graphic design.
To let Microsoft know that you think Publisher is worth keeping, send feedback in the portal at https://feedbackportal.microsoft.com/feedback . Alternatively/also, you can vote for an existing suggestion, of course. Sending feedback is important, because decision makers at Microsoft do not read Q&A (they do read feedback sent to them in the portal).
You can continue using Publisher if you have an older one-time payment license that includes the program. As suggested elsewhere (here and in other Q&A threads), you can get Office Professional 2021, but note that it is no longer sold by Microsoft, meaning that you must be careful if you purchase it from a third-party (non-Microsoft) seller or if you purchase it privately from an individual. Do not purchase Office Professional Plus, as those versions are usually volume license, and not appropriate if you are an individual user (home user) who needs a consumer product.
Third-party apps such as Affinity by Canva can open and edit Publisher files that have been converted to PDFs, which may be an option. Long-term, learning a new page layout program is probably the way to go.
You may be able to transfer file content into Microsoft Word, but it will usually require that you make use of copy & paste, so it might not be the best choice, especially if you have many files.