How to make a For Loop using mutate() function

Question

I am trying to index multiple columns of data and do not want to have multiple lines of code running.

Example:

df1 <- data.frame(
  A= c(245, 1124, 1256),
  B= c(548, 1145, 1248),
  C = c(234, 1348, 1594),
  D = c(231, 1124, 1354),
  E = c(354, 1784, 1942)
)

library(tidyverse)

list <- c(A, B, C, D, E)

df2 <- df1 %>%
 mutate(A = A/A[1]-1) %>%
 mutate(B = B/B[1]-1) %>%
 mutate(C = C/C[1]-1) %>%
 ... %>%
 ...

Unlike the example above, I have over 10 columns and over 100 rows of data, and I need to index to the 11th row and want to try using a 'for loop' to help me do this. I am very new to for loops so I am trying to learn the best way to get this done.

This is what I've tried:

for (list in df1) {
 mutate(df1, list = list/list[1]-1)
}

I have also seen other threads recommending to use mutate_(), but I am not sure what the difference is.

Any help will be appreciated - my first question on Stack Overflow!