Something like this?
library(dplyr, warn.conflicts = FALSE)
library(stringr)
df <- tribble(~ `Machine Name`, ~ Region,
"1233.corp.pdo.om", "APAC",
"xyz.om", "Europe",
"345.corp.pdo.cm", "Europe",
"abc12.cm", "Americas")
mutate(df, Region = if_else(str_detect(`Machine Name`, "corp.pdo"), "pdo", Region))
#> # A tibble: 4 x 2
#> `Machine Name` Region
#> <chr> <chr>
#> 1 1233.corp.pdo.om pdo
#> 2 xyz.om Europe
#> 3 345.corp.pdo.cm pdo
#> 4 abc12.cm Americas
Created on 2020-07-20 by the reprex package (v0.3.0)