To reset questions - use a web browser ,
Go to iforgot.apple.com and enter your Apple ID address and click on continue .
Check the box of I need to reset my security questions and click on continue .
Enter the Apple ID password and click on continue .
Check the box of answer your current security questions and click on continue .
A single question will be written in the field , enter the answer for it in the next field .
If you click on drop down arrow in the field you will view all the questions when the Apple ID was created , it’s your choice select any one of them and answer for that question .
And click on continue .
A pop up window will appear click on drop down arrow in each field , select the desired question and type the answer in the next field , apply the same procedure for rest of fields and click on continue the security questions are changed .
Take a screen shot of questions and answers and save them in notes or can write down in a diary for your records .
See this article also https://support.apple.com/en-in/HT201363