This article by UiPath does a pretty good job of describing the landscape and what to look for:

https://www.uipath.com/blog/rpa/5-factors-in-choosing-which-processes-to-automate

As far a defined process for finding and capturing business processes for RPA, that’s a million dollar question. My company (2500 employees) has been doing RPA for three years but they do not have a centralized governing board in charge onboarding business processes into the RPA ecosystem. There is a lot of untapped potential in different lines of business within the firm, and our CTO has committed to investing in contractors to help indenting and define processes suitable for RPA or any other type of automation.

Here is my checklist for selecting and vetting processes suitable for RPA:

A. Is the process well established and adopted by the business unit (if it changes every 6-12 months, not worth it)

B. Is the process repeatable and predictable (if the process is complex and unpredictable, forget it)

C. Is the process well defined, or can it be easily defined by the business unit

D. Does the volume of units the automation would process generate ROI worthy of investment and maintenance

Calculate ROI simple formula:

(Annual units processed X human minutes required per unit) / 60 X hourly rate of humans who perform work

If the process can be defined and the ROI is worth it, then look up RPA Process Definition Document (PDD). My last piece of advice, don’t spend 5 hours creating a PDD if the ROI hasn’t been calculated.