Pass the usename and password in Jenkins and store in local text file

I am working on a Jenkins job.I want to store some username and password for e.g

db.username=muqm
db.password=muqmt2

in Jenkins.My Job will start and then it will pass these values and add it to the local.properties files which will create from the jenkins job.The credentails should be store in below format in local.properties file

local.properties  {file name}
db.username=muqm
db.password=muqmt2

Can someone let me know how could I store the multiple username and password atleast 15-20 and pass it and store it into the local.properties file{will create from the Jenkins job}