Just use regular expressions.
For an email address just use the regular expression for at least one letter or number followed by @ followed by at least one letter or number a dot and at least one more letter, so:
a@b.c
could possibly be an email address as could somereallylongname@company.com
ect. a possible re would be \w+@\w\.\w
Telephone numbers would be, depending on whether you are looking for long distance numbers only, something like \d{2}[ -]*\d{3}[ -]*\d{3,}
but you might be better off locating potential phone numbers with a regex then using the google libphonenumber java/JS library which is a much more sophisticated library for checking and validating phone numbers and allows you to check if something is a possible phone number and if it is a valid phone number.