Syntax for using Oracle Linked Server with USE keyword
The USE command changes the database context to the specified database or database snapshot in SQL Server. I believe there should be a query with matching columns after your INSERT statement that would be the source for the INSERT. It may be OPENQUERY and could look like the following:

Insert into LHR_MIGRATION.dbo.Z_MIGRATION_TABLE
    (AMOUNT_TYPE
    ,BUSINESS_UNIT
    ,LEDGER
    ,ACCOUNT
    ,DESCR
    ,DEPTID
    ,DESCR_1
    ,PRODUCT
    ,JOURNAL_DATE
    ,JOURNAL_ID
    ,CURRENCY_CD
    ,MONETARY_AMOUNT
    ,FOREIGN_CURRENCY
    ,AFFILIATE
    ,PROJECT_ID
    ,LINE_DESCR
    ,DESCR254
    ,DOC_TYPE
    ,DOC_SEQ_NBR
    ,JRNL_LINE_SOURCE
    ,JRNL_LN_REF
    ,JOURNAL_LINE
    ,STATISTIC_AMOUNT
    )
SELECT AMOUNT_TYPE
    ,BUSINESS_UNIT
    ,LEDGER
    ,ACCOUNT
    ,DESCR
    ,DEPTID
    ,DESCR_1
    ,PRODUCT
    ,JOURNAL_DATE
    ,JOURNAL_ID
    ,CURRENCY_CD
    ,MONETARY_AMOUNT
    ,FOREIGN_CURRENCY
    ,AFFILIATE
    ,PROJECT_ID
    ,LINE_DESCR
    ,DESCR254
    ,DOC_TYPE
    ,DOC_SEQ_NBR
    ,JRNL_LINE_SOURCE
    ,JRNL_LN_REF
    ,JOURNAL_LINE
    ,STATISTIC_AMOUNT
FROM OPENQUERY(LinkServerName,'SELECT AMOUNT_TYPE
    ,BUSINESS_UNIT
    ,LEDGER
    ,ACCOUNT
    ,DESCR
    ,DEPTID
    ,DESCR_1
    ,PRODUCT
    ,JOURNAL_DATE
    ,JOURNAL_ID
    ,CURRENCY_CD
    ,MONETARY_AMOUNT
    ,FOREIGN_CURRENCY
    ,AFFILIATE
    ,PROJECT_ID
    ,LINE_DESCR
    ,DESCR254
    ,DOC_TYPE
    ,DOC_SEQ_NBR
    ,JRNL_LINE_SOURCE
    ,JRNL_LN_REF
    ,JOURNAL_LINE
    ,STATISTIC_AMOUNT
    FROM SourceTableName');


LinkedServerName would be the real linked server name and SourceTableName would be the name of the table in the linked server.