G'day gowthamvels,

I want to use a if conndtion like below ...

 if ($col6 =~ /^\Q97517\E/ }
    elsif
 $col6 =~ /^\Q97516\E/))
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The very first thing you should do is read "Perl introduction for beginners" because, from what you've demonstrated, you do not, at present, have a basic understanding of Perl code syntax.

if can be used in a compound statement. The construct looks like this:

if (CONDITION) {
    ACTION_WHEN_CONDITION_IS_TRUE
}
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That may be followed by zero or more alternative conditions and actions:

elsif (ALTERNATIVE_CONDITION) {
    ACTION_WHEN_ALTERNATIVE_CONDITION_IS_TRUE
}
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Finally, all of that may be optionally terminated with:

else {
    ACTION_WHEN_CONDITION_IS_FALSE
}
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This is documented in "perlsyn: Compound Statements".

if may also be used as a statement modifier:

ACTION_WHEN_CONDITION_IS_TRUE if CONDITION;
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This is documented in "perlsyn: Statement Modifiers".

There is also an "if pragma". This does not appear to have anything to do with what you're currently attempting; however, be aware of it to avoid confusion in other (unrelated) code, discussions or documentation.

Perl has no builtin if() function. I mention this because "if()" has been used in a number posts in this thread (including by yourself: "I am asking for how to use the if() in this code") and that usage could be confusing to a Perl novice.