Apply for visitor visa. You need to show funds in bank accounts to afford to travel, ties to home country (job letters with approved leave, businesses, properties, tuition paid), travel history and reason to travel.
You apply through the link that I provided, fill out the application for each person including bank accounts to afford visit, ties to home country, travel hisotry , pay the fees and then wait for biometrics letter. Depending where you live processing can be months with a high chance of refusal. Where do you live?
So I have provided the link for you to apply. You must show bank accounts/liquid funds to support a visit. Ties to home country like job letter with approved leave, business, tuition paid, investment property. Travel history to the US, UK, NZ or AUS. Proceasing is about 6 months and you will need to do biometrics. Good luck.