What do you mean; that appear always ?

You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Tapufind is a potentially unwanted program that is spread with the help of software bundling. If you installed apps from unknown sources and used Recommended installation settings, there is a high chance your PC is infected with various PUPs.

I need to eliminate Tapufind how an engine searcher of Firefox After to eliminate of preferencesm that's not enough,,, Another time appears as an unwanted program

See : https://malwaretips.com/blogs/remove-search-tapufind-com/

Please, also follow the advice given by FredMcD.

OK.

Eliminated