ChessBase can read and write databases in different formats:
The ChessBase format (extension CBH)
This is the native format, with powerful indexes and fast searches across multiple databases. It also supports a large number of annotation features, including graphic and spoken commentary, videos, text reports, and many other functions described in this reference. Double-clicking a file with this symbol will automatically start ChessBase and open the database.
The book format (extension CTG)
This is the database format for openings books.
The PGN format (extension PGN)
"Portable game notation" is a text format that is very popular for E-mail and on the Internet. Most chess playing programs can handle PGN.
This is how to create a PGN file:
In the database window click Application Menu – New – Database. In the database file manager select "PGN" as the file type. Use Drag & Drop to copy games into the new database. They are automatically converted into the PGN format.
This is the file format of earlier versions of ChessBase. You can right-click a CBF database and use "Convert to new format" to make it a CBH file.
ChessBase now supports a new database format with the extension *.cbone. This format is listed in the dialogs for opening and saving files. The advantage of this format is that in contrast to the CBH format the whole database is stored in one file. This makes the format suitable for backups and for sending to other people. If you use a large number of small files you should consider using this format. It is possible to exchange games between CBH, CBF and PGN databases. You can create databases in any of these formats and copy games into it.
See also List of all filenames.