Refer any research paper or database link or any content for review of literature on the said topic of Financial Inclusion/ Financial Literacy study anywhere.
There are many instruments that have been developed as financial literacy is such a nebulous and all-encompassing concept. Probably the best know instrument, and one which has served as the basis for many researchers' questionnaires is the Jump$tart coalitions' instrument. An example of it and its application can be found at http://www.jumpstart.org/assets/files/2008SurveyBook.pdf
An early and influential paper on financial literact which is useful as a starting point and has the added bonus of including its questionnaire is Haiyang Chen and Ronald P. Volpe (1998). An Analysis of Personal Financial Literacy Among College Students. FINANCIAL SERVICES REVIEW, 7(2): 107-128
Please see through "THE G20 BASIC SET OF FINANCIAL INCLUSION INDICATORS " at www.gpfi.org/featured/g20-basic-set-financial-inclusion-indicators . I hope this will also be helpful to shape up your research.
Organisation for Economic Co-operation and Development (OECD) through its arm for financial education, the OECDInternational Network on Financial Education (INFE), came up with a set of 19 core questions to measure financial literacy in 2010
The basic thing you have to bear in mind is to know what "Financial Inclusion" covers and try to capture these basic pillars in your questionnaire. To help you familiarize with the basic components of financial inclusion I have attached one material and in addition I recommend to see a new book on financial inclusion published by Elsevier, recently June 2019 under the title "Extending Financial in Africa" a collection of papers.