To read a file, open it, then read from it. The safest way is a with block, which closes the file for you when the block ends, even if an error happens inside it:

# First, make a small file to read
with open("poem.txt", "w") as f:
    f.write("The fog comes\non little cat feet.\n")

# Now read it back
with open("poem.txt") as f:
    text = f.read()
print(text)
print(len(text), "characters")

open("poem.txt") opens a file for reading. f.read() gives the whole file as one string, including the \n at the end of each line.