If you’re used to BINARY files, you can just PUT your text to the file and append a CHR$(10) after it.
text$ = “Hello World”
PUT #1, , text$ + CHR$(10)
A second method is just to open for OUTPUT and then PRINT to the file.
OPEN “temp.txt” FOR OUTPUT AS #1
text$ = “Hello World”
PRINT #1, text$
CLOSE