Add a line to a file

Hi
I want to search for a string and add a new line after that line in the file.
Say I have a file

Input file
adfad
aadfsdfsa
adfadsf
<name>TypeOptions</name>
adfdasf
adfad
adfad

outputfile
adfad
aadfsdfsa
adfadsf
<name>TypeOptions</name>
<option xsi:type="metadata:Option" value="300"></option>
adfdasf
adfad
adfad

Can you please help me with this ?

Thanks and Regards
Ammu

next time, show what you have got. After 70++ posts, you should have more experience already
see here for similar example

Hi,

# more infile
adfad
aadfsdfsa
adfadsf
<name>TypeOptions</name>
adfdasf
adfad
adfad
# more lineadd.sh
#!/bin/sh
echo "Enter the pattern to search ?"
read pattern
echo "Enter the line to add ?"
read line_add
while read line
do
ch1=`echo $line|grep $pattern|wc -l`
if [ $ch1 -ne 1 ]
then
        echo $line >> outfile
else
        echo $line >> outfile
        echo $line_add >> outfile
fi
done < infile
# ./lineadd.sh
Enter the pattern to search ?
name
Enter the line to add ?
found the pattern "name"
# more outfile
adfad
aadfsdfsa
adfadsf
<name>TypeOptions</name>
found the pattern "name"
adfdasf
adfad
adfad

code:-

sed  '/<name>/ { a\
<option xsi:type="metadata:Option" value="300"></option>
}' file.txt > out_file

Best Regards