Better way to make text appear smoothly ?

With your code, you would have to change the entire thing if you had a different string.

local str = "Taser"
txt.Text = ""
for m in str:gmatch(".") do
    txt.Text = txt.Text .. m
    wait()
end

I first created a variable with the string "Taser", so you could change this later, and made sure txt did not have any text in it. Then, I made a loop that goes through each of the characters in str and adds that character to txt's text.

If you wanted to make it delete each character, you could do:

while #txt.Text >= 0 do
    txt.Text = txt.Text:sub(1, -2)
    wait()
end