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 --env PATH "$CONDA_PREFIX/bin:\$PATH"

If you want to make your own Python virtual environment visible in Jupyterlab, the steps are similar:

source /path/to/myVenv/bin/activate
pip3 install ipykernel
python3 -m ipykernel install --user --name=myVenv --env PATH "/path/to/myVenv/bin:\$PATH"

To remove your personal kernels from Jupyterlab once you don't need them anymore, you could do so with:

jupyter kernelspec uninstall myKernelName