O tTravel to the bBeach

"O" is an archaic word used before people's names when you are addressing them, ie. "O John, what is the answer?"

In oOctober of this year (2025), my friends an my are beingre planning to travel to cCartagena c, Colombia, t. That place is so beatutifull, and the culture is amaizing.

All months' names are capitalized.
"being planning" is not correct because two "ing" endings cannot be used at the same time

O travelA Trip to the bBeach

I’m not sure what the “O” means here, I’m assuming you tried to say “I travel to the beach”?
But that phrase can sound a bit weird, so I changed it to “A Trip to the Beach”.

Additionally every word in a title should be capitalized except for articles (a, an, the), short conjunctions (and, but, or), and short prepositions (in, on, at, by). These are only capitalized if they are the first word in a title.

In oOctober of this year (2025), my friends an myd I are being planning to travel to cCartagena c, Colombia, t. That place is so beatutifull and the culture is amaizing.

1. A few capitalization mistakes here. Every month of the year is capitalized, and so are the names of cities and countries.
2. I believe you should end this sentence after the word “Colombia”, as there is no preposition or connecting word before “That”
3. Also a few spelling errors at the end

I can´’t wait to arrivego!

The word “arrive” is typically used when you’re currently on your way to some place. The word “go” fits better here

O tA Travel to the bBeach

Titlecase, though it's not necessary if you're not being serious.

In october of this year (2025), my friends an myd I are being planning to travel to cCartagena c, Colombia, t. That place is so beatutifull and the culture is amaizing.

The phrase you want is "my friends and I" like "my family and I," or "my brothers and I."

Delete "being" because you already have "are"

We capitalise place names, so Cartagena, Colombia. And comma in between.
The second half of your sentence is independent, so I made it it's own sentence. If you want, you can connect them by adding a conjunction, like "because" : "...my friends and I are planning to travel to Cartagena, Colombia, because that place is so beautiful and the culture is amazing."