Do you mean the default sample rate and bit depth when creating a new file? (File> New) If you set the desired parameters for a 'New' file, subsequent new files 'should' be the same. If they are not, the default new file attributes can be reset in a (hidden) menu which should not be messed with by inexperienced users (like the Windows OS registry).
When an existing file is opened in Sound Forge, the playback sample rate and bit depth will be the same as the file's. If the playback sample rate was different, the file would playback faster or slower and raise or lower the pitch.. just like a sped up or slowed down analog tape.

btw, welcome to the Magix Sound Forge users community @Bruce-Rounds