Create a new doctype that stores a list of names (like gender doctype)

please I want to add a custom field of type link to the customer doctype, but to do this i have to create another doctype that contains the list of the select-able options. I don’t want to create the field as type select with all the options because i want to be able to be continuously creating the select-able options on demand.
Thank you

Search for ‘Doctype List’ → New → Name: Gender, module: your custom app name
add 1 fields of type ‘data’ called gender
At the bottom, you can change ‘Auto Name’ to ‘gender’ (needs to be the name of your field)
Search for ‘Customize Form’, select Customer, add a row wherever you want and set it as ‘Link’ and in Option : Gender

I would suggest to look this: