Learn Icelandic: Anna kemur til Jóns. - Anna is coming to Jon's.

In Icelandic, the preposition til (to) always forces the noun that follows it into the genitive (possessive) case. For masculine names like Jón, the genitive form is made by adding an -s, becoming Jóns.

Is til Jóns used exactly like "to Jon's" in English?

Yes! Just like in English, saying til Jóns implies she is going to his house or place. You don't need to add an extra word for "house".

What is the dictionary form of the verb kemur?

The base form is koma (to come). Because the subject of the sentence is Anna (she), the verb takes the "he/she/it" form, which is kemur (comes or is coming).

Will I always use til when I want to say "to"?

Not always. Icelandic uses different prepositions depending on where you are going. However, til is exactly the right word to use when your destination is a person or someone's home.