I created my BTC Electrum wallet in the android app, however I do not remember having created the private key only to seed so that now I can not send the BTCs that are on it, when I open the wallet on a computer the following sentence appears:
So you have the seed words? If so, you need to use that to "restore" your wallet on the PC.
On PC: "File -> New/Restore -> Standard Wallet -> I already have a seed"... then enter your Seed words from Android App... it should then recreate a wallet identical to the one on your Android device. If you have a watching only wallet, it sounds like you only imported using the addresses or the "Master Public Key". This means you don't have the private keys stored on the computer, so you can't sign transactions as required to be able to spend coins.
If you don't have the seed, you should be able to see it on your Android device by tapping the wallet name/balance at the top of the screen (it will show "Master Public Key"), tap the "show seed" button and enter your PIN.