There is no specific requirement for encoder cable. For short distances (several meters) it is enough to buy 7x0.14mm2 shielded cable from a local producer/distributor.
But for big distances, bear in mind voltage drop. The instruction sheet of the dedicated encoder (example from ATV930 HTL encoder card VW3A3424 here below) shows minimum cross-section depending on encoder cable length and consumption.

Also check the encoder signals required by the encoder manufacturer whether 6 wires (A, nonA, B, nonB, Supply+, 0V) are enough.
For example 1XP8032-xxx Incremental HTL encoder from Siemens:
https://support.industry.siemens.com/cs/attachments/27102847/MA_IN_1XP8012_1XP8032-1xHTL.pdf?download=true

If the incremental encoder is equipped with a standard M23 connector (male), then it is also possible to buy a prewired cable + encoder connector (M23) from various local producers. Because Telemecanique sensors are no longer part of Schneider Electric, such cables are not in Schneider Electric's offer (In the past, there was for example XCCPM23121L5 offered by Schneider Electric).
I recommend searching on the web: "Pre-wired M23 female connector for incremental encoder, cable 5 m" and finding your manufacturer or distributor.

Released for: Schneider Electric Saudi Arabia