Newbie question; can a particular digital signature work for several transactio

[NdaMk]

A digital signature is created by combining a private key with transaction data. It's used instead of a public key or an address.
In a Bitcoin transaction, a digital signature is utilized to open an unspent output with the address save from the network

My issue is whether this signature can be used for several transactions.

[BlackHatCoiner]

It's used instead of a public key or an address.

It's used along with the public key, to verify the ownership.

My issue is whether this signature can be used for several transactions.

It can't, because in each transaction you need to include the input, which is the id of another transaction (and many other values[1]). Each transaction is unique due to this identifier, which is the id (AKA TXID or transaction hash). You can't have the same signature, because you need to sign an entirely different message each time.

[1] https://learnmeabitcoin.com/technical/transaction-data

[hosemary]

My issue is whether this signature can be used for several transactions.

If this was possible, anyone could steal other UTXOs from your address.
Note that any data you broadcast (including your digital signature) is public and anyone can see that. This is exactly why for proving our ownership, we broadcast a signature instead of our private key.

[pooya87]

A digital signature is created by combining a private key with transaction data.

It is not "combined", the transaction is the result of a mathematics formula where the inputs are the private key and a hash computed from the transaction. This signature can not be used for another transaction because if you change the variables in that formula (eg. the transaction) you get a different result.

[Charles-Tim]

With the private key and the transaction data, digital signature can be created, but created in a way the private key can not be known through the digital signature created. The transaction data, digital signature and the public key are then all needed to make a successful transaction. Digital signature is generated in a way private key is protected from exposing.

[Hyphen(-)]

My issue is whether this signature can be used for several transactions.

No. A digital signature is created to claim the ownership of our output so as not expose our private keys for security reasons. Digital signatures were made from our private keys and a particular Transaction data you are to use to unlock the transaction output. Therefore if you try using digital signature of a particular Transaction for another transaction it will not be accepted by bitcoin network.