The tones can be edited with the onboard minimal set of synth tools, and saved to the floppy.
The styles and rhythms can also be edited and similarly saved to disk.
I remember that there are 32 onboard user storage locations for sounds, and 10 user styles/rhythm patterns.
There is a conversion utility on the wk1800's factory floppydisk that's supposed to convert Roland and Technics styles, but I never got around to testing that before gifting it.
The WK is an amazing value for a 76 note keyboard with disk, but there are several important limitations:
no tap tempo
no incoming sysex storage to the internal disk (it sends a bulk dump, and will receive one meant for itself - but the floppy is useless as a midi data filer - weird)
Will play Standard MIDI Files (SMF0 only) from the disk drive, but will NOT save sequences as a SMF
Sequencer is not even slightly user-friendly, and is mainly useful as a scratchpad single track recorder.
The WK sounds very good with the onboard speakers, and the large display and excellent control panel make playing the board very easy.
The Soundset is General MIDI, and sounds like GM, but there are some excellent factory sound combinations above #130 that make the instrument useful.
Hope this helps.