All of them are correct and their actual translation is “I’m glad to meet you”, which also serves to mean “It’s nice to meet you”. Which one to use though would depend on whom you are addressing. “Ikinagagalak” and “ikinalulugod” both mean “glad to”, though the latter is rather old-fashioned and therefore rarely used now. “Ikinagagalak ko kayong makilala” – is formal. You use it to address an older person, a superior, an official, etc. It is also used to address a group (the plural “you”). This may also be said as “Ikinagagalak kong makilala kayo”. “Ikinagagalak kitang makilala” or “Ikinagagalak kong makilala ka” – is informal. You use either this to address a peer or a younger person.

1.) Ikinagagalak ko kayong makilala-First person "ko" (I'm) is used. Second person "kayong" means more than one. This sentence is applicable when you are referring to persons. 2.) Ikinalulugod kitang makilala-"kitang" means singular. This is applicable when you're referring to a person. 3.) Ikinalulugod kong makilala ka- this is just the same with sentence#2, but in different form. First person "kong",(I'm) is used, and second person"ka"(you) is added. *Ikinalulugod and Ikinagagalak have the same meaning.(glad)

1.) Ikinagagalak ko kayong makilala-First person "ko" (I'm) is used. Second person "kayong" means more than one. This sentence is applicable when you are referring to persons. 2.) Ikinalulugod kitang makilala-"kitang" means singular. This is applicable when you're referring to a person. 3.) Ikinalulugod kong makilala ka- this is just the same with sentence#2, but in different form. First person "kong",(I'm) is used, and second person"ka"(you) is added. *Ikinalulugod and Ikinagagalak have the same meaning.(glad)

I don't know if if will be helpful for you, but It helped me to understand the role of each of these words how the meaning is reached. Ikinasasaya / ikinagagalak / ikinatutuwa -sort of means a noun, a thing, that has an effect of making something or someone more like the root word. like 'that which is making me happy'. Note that it contains a tense, and you could make it completed tense by saying 'ikinasaya...' which would allow you to say 'it was lovely to meet you'. ko - this possessive pronoun is attached to the first word. It is not in focus, and therefore, it is 'the thing that was made happy' instead of 'the thing that caused more happiness'. Kayo / ka - this active pronoun is the focus of 'ikinisasaya'. Thus it becomes 'the thing that made me happy Makilala - Ma words usually express the capability to do something. Kilala is like recognition or familiarity. Thus, makilala is like 'To be able to get to know sth' Lastly, the ng attached to Kayo is important. It links kayo+makilala meaning that actually it is 'getting to know' and 'you'. Without it, it's more like 'You make me happy, getting to know'. Therefore you will see kitang makilala or Kang makilala or kayong makilala. I hope this is all correct. I also hope it's helpful to you, I find this level of understanding on sentence structure to be important, given the difficulty i have in learning the importance of focus in a sentence compared to word order in English.

I'd just like to add this to Henry's input. There's also "Ikinasasaya" with the word "saya (happiness)" to replace Ikinagagalak or Ikinalulugod. Some folks would rather say "Ikinatutuwa" from the root word tuwa (happiness). It varies for every Tagalog region. My friend from Laguna prefers Ikinagagalak, while Ikinatutuwa will do fine for me. :)