As non-British citizens your children will most likely require visas to legally enter the country.

There are various visa’s that you may be able to apply for, the choice is at your discretion and in relation to the purpose for the visa.

One example of a visa which would allow your children to enter the UK is, a standard visa. This visa is suitable for short stay trips and it last for 6 months. There are other eligibility requirements and a fee. I will include a link below please note this is not exhaustive: https://www.gov.uk/standard-visitor-visa

Another example is a family visa. This allows British citizens or those with settled status to bring their families to reside in the UK with them. There are more eligibility requirements, a fee and supporting evidence necessary when making an application. This visa allows the holder to study/ study and can be a route to gaining British citizenship. I will include a link below, please note this is not exhaustive. https://www.gov.uk/uk-family-visa/after-you-apply

I suggest you review the guidance in order to determine the best suited visa. The UK does have other visas, I have only suggested two.

Please note, that as you might be traveling from the Philippines, due to the pandemic the UK has travel restrictions in place. As of today, the Philippines is currently on the UK’s red list, therefore the UK is only allowing individuals who are British, Irish or have residency rights in the UK to enter the country from the Philippines. It appears these restrictions might affect your family during the move, as your children are not currently British or have residency rights in the UK. https://www.gov.uk/guidance/red-amber-and-green-list-rules-for-entering-england