It's easy to migrate your data from other reference management tools to Zotero. Instructions for popular tools are linked below.
You can also import from other tools, such as Reference Manager, RefWorks, Papers, Google Scholar Library, ReadCube, etc., by exporting to a standardized reference format, such as RIS, BibTeX, or CSL JSON, and then importing into Zotero by clicking File → “Import…” and choose “A file”.
If you already have data in a Zotero library on another computer, follow these instructions to transfer your library to your new computer.