To use your own conda environment as a kernel for Jupyter notebook you will need to have ipykernel installed in the conda environment before starting your Jupyter instance. ipykernel can be installed with:
conda activate myCondaEnv conda install ipykernel python3 -m ipykernel install --user --name=myCondaEnv
If you want to make your own Python virtual environment visible in Jupyterlab, the steps are similar:
source myVenv/bin/activate pip3 install ipykernel python3 -m ipykernel install --user --name=myVenv
To remove your personal kernels from Jupyterlab once you don't need them anymore, you could do so with:
jupyter kernelspec uninstall myKernelName