What is the shared secret point in ECDH?

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What is the shared secret point in Elliptic Curve Diffie Hellman protocol? I mean is it text converted into numerics or is it a key to decrypt the text?What's the use of the point?

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A point on an elliptic curve is just a pair of large numbers modulo a (largish) prime $p$. The shared secret point in ECDH is usually written in bytes (so in base $256$ essentially) in a standard way (bigendian usually), with a separator between coordinates and the resulting bytes are hashed (SHA-256 is a common choice) to get a common secret for cryptographic use (like a symmetric key). The standards are mostly public, or else look at a cryptographic library like openssl to see the gory details, if you like.

Here you can see the prime fields for many commonly used curves, and here their base points (that generate large additive subgroups). Just to make it more concrete maybe.