How can you reference taxonomy term by another field in Yaml file? I created my own Yaml file with fields inside to migrate nodes.

I run into this problem.
If I use the feeds module, I can set (during mappings) that a given field (taxonomy term reference field) can be referenced by any other field from my site. The term name is therefore assigned based on the value in the reference field.

If I use Migrate CSV module, how do I set this in Yaml file?
This is my Yaml:

uuid: bf1e53ae-6a95-48f2-8888-4b928e6e33ea

id: testovacimigrace2
label: My own migration !!!!!!!
migration_group: migration

source:
  plugin: 'csv'
  # Full path to the file.
  path: 'modules/custom/migrace/assets/csv/upload1.csv'
  delimiter: ','
  enclosure: '"'
  header_row_count: 1
  ids:
    - ID

process:
  title: title
  field_email: email  
  type:
    plugin: default_value
    default_value: submitlawyer 

destination:
  plugin: entity:node



Every term in my taxonomy called "fishes" has its own field with a unique number.
My CSV contains a column called fish that does not contain a term name but its unique number (ad.1)
I need to assign the correct term by using this unique number.
Here is a simple migration for looking up a taxonomy term by name based on the text in a CSV.

taxonomy_field_name:
  plugin: entity_lookup
  source: name_of_source_column
  value_key: name
  bundle_key: vid
  bundle: name_of_taxonomy
  entity_type: taxonomy_term


For example, if you have a taxonomy called fishes, and your CSV has a column called fish, and your node has a field called field_fish which is an entityreference to a taxonomy term of the fishes vocabulary, and there is a taxonomy term "Carp" with entity ID 14

field_fish:
  plugin: entity_lookup
  source: fish
  value_key: name
  bundle_key: vid
  bundle: fishes
  entity_type: taxonomy_term


Given a row in the CSV with "Carp" set as the fish, this will assign entity id 14 to that field.

Does that help?  I am not sure what you mean by "a given field can be referenced by any other field from my site".